Estratigrafía secuencial y sedimentologÍa del Jurásico superior del noreste de Albacete

Abstract

A Sequence Stratigraphic analysis carried out in the Upper Jurassic of the linking area between the Betic and Iberian Ranges (Albacete, SE Spain) has resulted in the identification of two depositional sequences (i.e., Kimmeridgian and Tithonian-Berriasian Sequences). Further division of systems tracts in the lower sequence was based on extensive facies analysis. This analysis also gave new information on the transition from inner to outer areas in the Kimmeridgian ramp. During lowstand systems tract, after a basinwards coastal shift, a deltaic prograding complex is observed in middle ramp areas. At the onset of the transgressive systems tract, flooding of the inner ramp areas was effective and fine grain carbonate deposition progressively covered the outer and middle ramp realms. Sandy and oolitic facies sharply prograded over middle ramp areas during highstand systems tracto During the Tithonian, a fast progradation of the bioclastic-peloidal facies (inner ramp) over the oncolitic- oolitic facies (middle ramp) took place. The comparison between the results reported here to others reached in previous works, allows to state that the overall evolution of the accommodation during the Late Jurassic was similar in the Iberian basin and resulted in a similar distribution of sequences and systems tracts. The driving mechanism creating the accommodation in the basin is interpreted to be related to regional, tectono-eustatic changes. Local differences observed on the facies are controlled by intra-basinal factors. In contrast to other marginal areas of the Iberian basin, which were dominated by high-amplitude oolitic sand-waves and extensive coral growing, marine restriction and larger c1astic input in the Albacete sector reduced the potential coral growing and diminished the effect of storms, as reflected by the lower amplitude of the oolitic bars.